The rowing competition at the 2016 Olympics will be held at the Rodrigo de Freitas lagoon in Rio de Janeiro. By all accounts the lagoon is usually very nice but it has run into a problem at the moment. There is currently a lot of dead fish in the water there. 65 tonnes of dead fish to be precise.
The authorities will probably need all of the next three and a half years before the Olympics to clear this waterway.
h/t deadspin